The reverse of the Etruscan mirror renders an engraved scene with four figures interpreted as Paris and Helen in conversation with the Dioscuri, Castor and Polydeukes (lat. Pollux). In the background an architectural structure, possibly the gable of a temple, is suggested. The Dioscuri were brothers and, as the name suggests, sons of Zeus (the Greek Dios is the genitive of Zeus, while kouros means young man). But in fact Zeus was the father only of Polydeukes, who was therefore immortal. Castor, who was the son of Tyndareus, was on the other hand mortal. The two brothers were inseparable, and when Castor was mortally wounded in battle, Polydeukes begged his father for help. So Zeus let the two brothers in turn live for one day on earth and for one day in the realm of the dead. The Dioscuri were a popular motif with the Etruscans. They are often represented on mirrors as unbearded young men dressed in short cloaks and carrying spear and shield. They are often also wearing Phrygian caps (known as piloi). Mirrors were typically articles for use in the upper strata of the Etruscan society. They were often made of bronze, but in rare cases also of silver. Many of the Etruscan mirrors, like this one, have a decoration engraved on the reverse. Unfortunately, we only know the find-contexts for a limited number of Etruscan mirrors. In these cases, they are typically found in graves. It is, hence, likely that the mirrors in Thorvaldsen’s collection of antiquities all derive from the excavations of one of the Etruscan burial sites north of Rome in the 1820s and 1830s.